The long-range aim of this research is to study the function of neurotransmitters in the maintenance of behavior and the mediation of the action of drugs affecting behavior. The research will focus on dopamine, norepinephrine and 5-hydroxytryptamine and their relationship to operant behavior. Psychomotor stimulants, tricyclic antidepressants, and antipsychotic agents will be the main drugs studied. Locomotion, feeding and drinking will also be considered as they relate to operant behavior. The neurotransmitters in the CNS will be modified by using drugs and/or neurotoxins. Behavior will be measured by using various operant techniques and the control and analysis of the data will be computer oriented. There are three major areas of interest upon which this research will focus. First, the effects of drugs acting on monoaminergic systems; second, describing interaction between behavioral, environmental, and pharmacological variables in effecting monoamine metabolism; and third, the behavioral, pharmacological, and neurochemical aspects of tolerance to drugs affecting the monoaminergic systems.